Date: Sat, 30 Jun 2007 08:59:11 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Arne =?iso-8859-2?Q?W=F6rner?= <arne_woerner@yahoo.com> Cc: Harry Newton <hn+freebsd@yewbarrow.net>, freebsd-geom@freebsd.org Subject: Re: gmirror on a slice uncertainty Message-ID: <20070630065911.GB28006@garage.freebsd.pl> In-Reply-To: <99891.46426.qm@web30301.mail.mud.yahoo.com> References: <20070629220604.GA28006@garage.freebsd.pl> <99891.46426.qm@web30301.mail.mud.yahoo.com>
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--bCsyhTFzCvuiizWE Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 29, 2007 at 10:52:36PM -0700, Arne W=F6rner wrote: > --- Pawel Jakub Dawidek <pjd@FreeBSD.org> wrote: > > On Fri, Jun 29, 2007 at 07:46:33AM -0700, Arne W=F6rner wrote: > > [...] > > > I wouldnt use a bsdlabel on the gmirror device > >=20 > > Why? It's perfectly safe and useful. > > > Because he wants to use the whole device for his "home" file system... > So he just introduces a 16 sectors offset... Both methods (mirroring entire disks and mirroring only slices/partitions) have pros and cons. Mirroring entire disks: - after a crash/power failure entire disk has to be synchronized, which may take a long time, + when one replaces disk, he doesn't have to configure slices/partitions on new disk, because everything will be synchronized, + after a crash/power failure there will be only one synchronization process running for the disks. Mirroring slices/partitions: + after crash/power failure only those partitions that were actively used will be synchronized (gmirror marks devices as clean where there are no writes in few seconds) - when one replaces disk, slices and partitions need to be configured by hand, and all partitions inserted to existing mirrors, - after a crash/power failure gmirror will synchronize all partitions at once which puts very heavy load on disks - this should be corrected in the future and currently may be worked around. + allows for fancy configurations - I've machine with five disks, that have two 'a' partitions mirrored for root, three 'a' partition in graid3 for /usr/ and five 'd' partitions in ZFS/RAIDZ for /usr/home/. I use both methods depending on my needs. --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --bCsyhTFzCvuiizWE Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) iD8DBQFGhf8/ForvXbEpPzQRAug9AKCN5fb/xs9J6lT3X8UB0g5886NIsgCgq6t2 K4zg/DSGo/pSUuxEVuKFr+g= =d7tv -----END PGP SIGNATURE----- --bCsyhTFzCvuiizWE--
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